I don't know how to acquire the Advanced Shaolin Light Foot. The clan vender only sells lvl 2 advanced.
Most new players buy them from other player stands in hefei. You can also try checking the auction NPC for Shao books, or try asking your band members to donate them to you. The clan advanced tomes do drop in various dungeon runs with green and red passes, but that usually requires you to be mid level onwards to farm.